I have a air conditioner to cool a building and a hot water system to heat it.
Each have their own air mover (fan). They are being controlled by one conventional thermostat. The air conditioner it wired correctly except that the FAN wire isn't connected to the air conditioner air mover. FAN is connected to the hot water air mover. So..the heat has to be turned on and off manually. This is a very awkward situation. Anyone have any ideas on the best way to remedy this situation?

If it uses hot water for heating then perhaps the radiator is hot all the time and only the fan is turned on and off to control the temperature. In that case there wouldn't be a thermodisc switch to control the fan.